c++ google tests segfault when comparing int from deque

Here a snippet of code :

  // ...      

  std::deque<int> removed_ids;

  // write 2 values in removed_ids
  stack.remove(2,removed_ids);

  ASSERT_EQ(removed_ids.size(),2);

  int foo = 3;

  // this is printed, and values make sense, e.g. foo is 3
  std::cout << "IN | " << removed_ids.back()<< " | " << foo << "\n";

  ASSERT_EQ(removed_ids.back(),foo);

  // segmentation fault, never printed
  std::cout << "OUT\n";

Running the tests always lead to a segmentation fault at the second ASSERT (the one comparing removed_ids.back() and foo) ; i.e. "OUT" is not printed in the terminal ("IN" is, followed by values of int that makes sense).

This is in a file running other tests, also doing some asserts, all working fine.

I am very confused of what may be happening.

I am on Ubuntu 16.04, c++11